1. Field of the Invention
The present invention generally relates image processing and more particularly relates to outputting images that have undergone various types of image processing.
2. Description of the Related Art
Imaging lenses typically used for cameras and the like have various types of aberrations, such as spherical aberration, astigmatism and comatic aberration. Among them, aberrations causing geometrical distortion of a captured image are called distortion aberrations. As typical measures for reducing the distortion aberration, a lens exhibiting minimized distortion aberration is designed.
However, lenses having the distortion aberration as-is have been used for special applications. For example, in a monitor imaging apparatus that is attached to the back of a vehicle and that captures images for rear-viewing, a fish-eye lens or the like to capture images of a very wide range at a super-wide angle is used so that a pedestrian who recognizes the existence of the vehicle but approaches without expecting reverse of the vehicle can be found without fail. Also, in a monitor imaging apparatus that is placed at an entrance and that captures images of visitors, a fish-eye lens or the like having a super-wide shooting range is used so that images of a person can be captured even if the person is at a position in a slanting direction with respect to the imaging apparatus.
In those lenses used for such applications, higher priority is put on imaging at a super-wide angle rather than on correction of the distortion aberration, and thus even significant distortion aberration of the fish-eye lens is left in many cases. However, since the fish-eye lens covers a view field of nearly 180 degrees, a subject near the edge of an image captured by the lens is distorted to a large extent, and it may be difficult to determine what a subject in the image is, e.g., a person or a pole.
Conventional vehicle-surroundings display apparatus capture images of situations around a vehicle and display the situations around the vehicle and a figure representing the vehicle on the same screen, so as to show a boundary of driving lanes to a driver. Such a conventional apparatus includes a television camera; a coordinate transforming unit, an area specifying unit, and an image signal generating unit to perform distortion correction and viewpoint conversion on the imaging signal and generate an image signal; a drawing signal generating unit to generate a drawing signal indicating the vehicle; an image combining unit to combine the generated image signal with the generated drawing signal so as to generate a display signal; and a display. With this configuration, the apparatus is expensive.
Also, a conventional multiplexing technique of combining two imaging formats of different resolutions exists. For example, an HD (High Definition) imaging signal is converted to an SD (Standard Definition) imaging signal of the NTSC (National Television Standards Committee) or the PAL (Pase Alternating Line) by a imaging resolution converting unit, a synchronization signal as that of SD imaging obtained by performing frequency division on the HD imaging signal and a synchronization signal based on the SD imaging signal are supplied to a memory control unit, OSD (on screen display) data is read from a memory and is combined with the SD imaging signal based on the respective synchronization signals, and the OSD data combined with the SD imaging signal is output. Such an apparatus is complicated and expensive.
An image processing method for displaying images and/or characters in a processed image corrected with various types of image processing and an imaging apparatus using the method have been demanded.